Electric ignition device.



J. E. GALLANT.

ELECTRIC GNITION DEVICE.

APPLICATION FILED SEPT. 21. 1914.

1 1 fifl Patented Dec. 14, 1915.

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JOHN E. GALLANT, OF BOSTON, MASSACHUSETTS, ASSIGNOB OF THREE-FIFTHS T0 ELMER R. BATCHELDER, OF BOSTON, MASSACHUSETTS.

ELECTRIC IGNITION DEVICE.

To. alt whom it may concern Be it known that I, JOHN E. GALLANT, a citizen of the United States, residin at Boston, in the county of Suffolk and tate of Massachusetts, have invented a new and useful Electric Ignition Device, of which the following is a specification.

This invention relates to an electric ignition device and particularly to that type of ignition device in which an auxiliary spark gap is used. Such a device is shown in my pending application, Serial No. 831,030, and my present invention is, to a certain extent, in t e nature of an improvement onthe construction therein shown.

It is the object of my present invention to increase the effectiveness of electric ignition devices as heretofore known, with economy of manufacture and simplicity of parts.

With this general object in view, one of the features of my present invention contemplates the provision of an auxiliary spark gap in series with the primary spark gap, the auxiliary spark being caused to traverse a mass of non-continuous and pref erably non-conducting material. It has been found that such material thus disposed materially changes the character of the primary spark and greatly increases its effectiveness.

Another feature of my invention consists in the provision of an improved form of insulating tube for supporting the inner sparking terminal, said tube being provided with circumferential external corrugations which increase the effect surface distance between the oppositely electrified parts of the ignition device.

My invention further consists in certain devices, arrangements and combinations of parts which will be hereinafter described and more specifically pointed out in the appended claims.

A preferred form of my invention together with a modification thereof is shown in the drawings in which Figure 1 is a longitudinal sectional view of a spark plug embodying my invention in, its preferred form; Fig. 2 is a detail view in elevation of those parts of the spark plug Specification of Letters Patent.

Application filed September 21, 1814. Serial No. 862,682.

Patented Dec. 141, 1915.

having metallic base 10 adapted to be in-' sorted in and secured to a support 11 which (11s usually a portion of a gas engine cylin' er. Within'the base 10 an insulating tube 12 is mounted, being secured therein by a clamping nut 13 screwed into the upper end of the base 10. The tube 12 is commonly formed of porcelain but other well known insulating materials may also be used. Me-

tallic' packing-rings 14 and 15 of the usual type separate the insulating tube from the base 10 and the nut 13, preventing the escape of gases from the cylinder.

One of the sparking terminals is indicated at 16, this terminal being mounted upon the base 10. The other terminal is formed as a rod 17 (Fig. 7 having a head,

18 at one end and extending vertically through the lower portion of the insulating tube 12. The lower end of the rod 17 is threaded to receive a binding nut 19 by which the stud is secured within the insulating tube. As the coeflieients of expansion of metal and of the material of the tube are not the same, I have found it advisable to interpose asbestos cushioning washers 20 and 21 between the ends of the.

rod 17 and the insulating tube. The lower portion of the tube is provided withexternal circumferential corrugations as shown in Fig. 1. These corrugations materially increase the effective 'surface distance between the base 10 and the nut 19.

In the operation of a spark plug the por tion of the insulating tube which extends downward through the recess in the base 10 eventually becomes coated with carbon and 011 and has a tendency to short-circuit the plug to short-circuit is correspondingly decreased.

The head 18 of the rod 17 or the washer 20 underlying the head rests upon a shoulder 22 at the lower end of a cylindrical recess 23 in the upper portion of the insulating tube 12. A threaded 'nut 24 overlies the upper end of the tube and is secured thereto by a metallic sheath 25 which'is placed over the nut 24 and is secured in positionby melted lead which is caused to flow between the sheath of the tube, thus filling the semi-circular groove 25, (Fig. 4) which surrounds the upper end of the tube and also the notches 26 above the groove.

A screw 27 is mounted within the nut 24 p and extends a substantial distance beyond it in both directions. One portion of the screw.

27 extends downward into the recess 23' and has its lower end slightly separated from the head 18 of the rod 17 The upper end of the screw 27 extends through a locking nut 28. and is provided with a binding nut 29.

Between the lower end of the screw 27 and the upper end of the rod 17, I provide a mass of dielectric material 30. This material may be of many different forms and compositions, the essential requirements being that it shall be in whole or in part anon-conductor of electricity but shall also permit restricted passage of electric current between the screw 27 and the rod 17 In order to confine the material within its proper position it has been found desirable to provide a thin asbestos plug 31 overlying the material 30. It is also desirable to line the recess 23 with a tube 32 of asbestos or similar material, the efiiciency of the spark being thereby increased.

In the commercial form of my invention, I provide the metallic parts with a thin coating of copper, which by its softness enables close joints tobe more easily secured and also prevents the rusting of the plug into the cylinder.

While the exact function of the material 30 in increasing the efficiency of the spark is difiicult to determine, it would appear that the interposition of the non-continuous di-. electric material causes the current to pass through a large number .of separate paths between the screw 27 and the rod 17. Whatever the function of the material, the character of the primary spark between the rod 17 utilized to form the mass 30, I have found that finely granulated or powdered mica is one of the most satisfactory. I have also successfully used a strip of mica rolled into a spiral coil fitting the tube 32 and sodisposed therein that the current passes between the spirally arranged layers. I have also used glass as a dielectric material, ob taining successful results by using two pieces of glass having a crack between them through which the current may pass... While these materials are all non-conductorsgof. electricity, it is not essential that the mass; 30 should be entirely formed of such material, as satisfactory results have also been obtained by using a mixture ofconducting and non-conducting materials, such, for instance, as fine metal fragments mixed with a finely divided-dielectric material, or with a cement which is non-conducting when set.

In such a mixture nickel is found to be very desirable. Many other materials may be used for this purpose, including certain liquids in addition to various-mineral substances; and I do not wish to be limited to the use of any particular dielectric material otherwise than as set forth in the claims.

It will be obvious that other kinds of cushioning material can be substituted for asbegtos in making the washers and lining tu e.

I consider it to be within the scope of my invention to dispose the auxiliary sparking deylce at any point in the high tension circu1t. In Fig. 8 I have shown a form of my invention in which the auxiliary device is shown as an insulating tube 40 having terminals 41 and 42 mounted therein and having the mass a dielectric'material 43 disposed between their inner ends. The outer ends of the terminals 41 and 42 are connected to the spark plug and the battery 44, or to some other source of high tension current, the operation of the device being substantially identical with that above outlined.

Having thus fully described my invention it will be evident that other changesand modifications can be made therein by those skilled in the art without departing from the spirit and scope thereof as set forthin the claims, and I do not wish to be limited to the details herein disclosed, but

What I do claim is:

1. In an electric ignition device, the combination of a spark plug having a primary spark gap, and means providing an auxiliary spark gap in series therewith,'said auxiliary means comprising separated conducting members forming the auxiliary gap, and a non continuous mass containing non-con ducting solid material confined within said auxiliary gap.

2. In an electric ignition device, the combination of a spark plug having a primary spark gap, and means providing an auxilspark gap, and means providing an auxiliary spark gap in series therewith, said auxiliary means comprising separated conduct 1 ing-members forming the auxiliary gap, and

a mass of fragments of'solid material forming a mixture of' conducting and non-conducting materials secured withinsaid auxiliary gap.

5. In an electric ignition device, the combination of a spark plug having a primary spark gap, and means providing an auxiliary spark gap in series therewith, said auxiliary means comprising separated conducting members forming the auxiliary gap, and a non continuous mass formed of a mixture of metal fragments and a non-conducting material secured within said auxiliary 6. In an electrlc ignition dev ce, the combination of a spark plug having a primary spark gap, and means providing an auxiliary spark gap in series therewith, said auxiliary means comprising separated conducting members forming the auxiliary gap, and a mass of nickel fragments and powdered mica secured within said auxiliary gap.

7. A spark plug having, in combination, a base with a spark terminal mounted thereon and connected to one side of a high tension circuit, an insulating tube supported in said base, a second spark terminal fixed in said insulating tube, a nut sealed to the top end of said tube and a threaded metallic member extending through said nut and connected to the other side of the high tension circuit, said member and said second terminal forming an auxiliary spark gap between their adjacent ends and being separated at their inner ends by a mass containing fragments of solid non-conducting material. v

8. A spark plug having, in combination, a base with a spark terminal mounted thereon and connected to one side of a high tension circuit, an insulating tube supported a said base, a second spark terminal fixed in said insulating tube, a nut, a sheath covering said nut and sealed to said tube and a threaded metallic member extending through said nut and connected tothe other'side of the high tension circuit, said member and said second terminal being separated at their inner ends and having a mass comprising fragments of solid non-conducting material confined between said ends.

9. .A spark plug having, in combination, a base with a spark terminal mounted thereon and connected to one side of a high tension circuit, an insulating tube supported insaid base, a second spark terminal fixed in said insulating tube, a nut, a sheath covering said nut, a lead packing between said sheath and the upper end of said tube effective to seal said sheath to said tube, and a' threaded metallic member extending through said nut and connected to the other side of the high tension circuit, said member being thereby adjustable longitudinally and efltective to compress a mass containing fragmentary non-conducting material between the end of said member and the inner end of said second terminal.

10. A spark plug having, in combination, a base with a spark terminal mounted thereon and connected to one side of a high tension circuit, an insulating, tube supported in said base, a second terminal fixed in said insulating tube, and a metallic member mounted in said tube and connected to the other side of the high tensionfcircuit, said member and said second terminal having their adjacent ends separated and having a non-continuous mass containing mineral material confined a nut fixed to said tube above said recess, a

rod extending into the lower end of said recess, a screw mounted in said nut and extending into proximity to said rod, frag mentary non-metallic material separating said rod and said screw, and a non-combustible, non-metallic washer separating said material and said screw and preventing the movement of said material toward the upper endof said recess.

13. A spark plug having,,in combination, a base with a sparking terminal thereon, an

insulating tube supporting a second terminal and a clamping nut to secure said tube in said base, the metallic parts of said plug having a thin exterior coating of copper effective to form a soft packing between the secured parts and to permit the easyremoval of said plug from its support.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

\ JOHN E. GALLANT.

Witnesses:

JAMES H; CANNEY,

ELMER H. SNOW. 

